LASER AND ENVIRONMENTAL MONITORING METHOD

• US 20090256071A1
• Filed: 06/22/2009
• Published: 10/15/2009
• Est. Priority Date: 01/30/2001
• Status: Active Grant

• Current Assignee: The Board of Trustees of Michigan State University (Michigan State University)
• Original Assignee: The Board of Trustees of Michigan State University (Michigan State University)
• Inventors: Dantus, Marcos, Comstock, Matthew, Lozovoy, Vadim V.
• Granted Patent: US 8,265,110 B2
• Time in Patent Office: Days
• US Class Current: 250/282
• CPC Class Codes: G01B 9/02014 by using pulsed light
• CPC Class Codes: G01B 9/02091 Tomographic interferometers, e.g. based on optical coherence
• CPC Class Codes: H01J 49/162 Direct photo-ionisation, e.g. single photon or multi-photon ionisation
• CPC Class Codes: H01J 49/164 Laser desorption/ionisation, e.g. matrix-assisted laser desorption/ionisation [MALDI] sample holders H01J49/0418
• CPC Class Codes: H01S 3/0057 Temporal shaping, e.g. pulse compression, frequency chirping soliton generation and propagation G02F1/3513, H01S3/063 and H01S3/108

Abstract

A laser and monitoring system is provided. In another aspect of the present invention, the system includes a laser, pulse shaper and detection device. A further aspect of the present invention employs a femtosecond laser and binary pulse shaping (BPS). Still another aspect of the present invention uses a laser beam pulse, a pulse shaper and a SHG crystal. In yet another aspect of the present invention, a multiphoton intrapulse interference phase scan (hereinafter “MIIPS”) method is used to characterize the spectral phase of femtosecond laser pulses and to correct them. A further aspect of the system of the present invention is employed to monitor environmental chemicals and biological agents, including toxins, explosives, and diseases.

Claims

1. A method of operating a system comprising:

(a) emitting a laser beam pulse at a specimen;

(b) varying the shape of the laser beam pulse;

(c) detecting a mass spectrum using the varied shape laser beam pulse;

(d) automatically generating multiple additional laser beam pulses of different shapes after steps (a)-(c);

(e) automatically and electronically analyzing the detected mass spectrum and ranking them based on closeness to a target spectrum;

(f) repeating steps (a)-(e) to statistically improve detected values; and

(g) ranking the likelihood that a compound has been detected and identified.

2. The method of claim 1, wherein the laser beam pulses are less than about 50 femtoseconds.

3. The method of claim 1, wherein at least one of the laser beam pulses is transform limited and less than about 35 femtoseconds.

4. The method of claim 1, wherein the specimen is a hazardous molecule.

5. The method of claim 1, further comprising:

(a) storing the selected and ranked mass spectra in a memory library;

(b) monitoring an environment of unknown chemicals; and

(c) automatically determining which chemicals in the environment are acceptable and which are unacceptable.

6. The method of claim 1, further comprising using a programmable controller to positively identify a previously unknown agent, if the agent is automatically determined by the controller to be harmful.

7. The method of claim 1, further comprising analyzing the specimen with the laser beam pulse in the breath of a person.

8. The method of claim 1, further comprising analyzing the specimen with the laser beam pulse in a building ventilation system.

9. The method of claim 1, further comprising analyzing the specimen with the laser beam pulse on clothing of a person.

10. The method of claim 1, further comprising detecting the presence of and identifying a disease in the specimen.

11. A method of monitoring an area comprising:

(a) monitoring specimens of the area in a repetitive manner;

(b) emitting shaped laser pulses at the specimens;

(c) comparing mass spectra obtained at least in part by step (b) with the mass spectra of acceptable background chemicals; and

(d) automatically identifying harmful items based at least in part on the mass spectrum comparisons.

12. The method of claim 11, further comprising monitoring the area in repetitive intervals of about one minute or less for a nominal condition.

13. The method of claim 11, further comprising monitoring the area in repetitive intervals which are automatically increased if suspicious items are identified.

14. The method of claim 11, wherein the monitoring, emitting, analyzing, comparing and identifying steps are all automatically controlled and operated by a computer.

15. The method of claim 11, wherein at least one of the laser pulses is transform limited and has a duration of less than about 50 femtoseconds.

16. The method of claim 11, wherein the laser pulses have a duration of less than about 21 femtoseconds.

17. The method of claim 11, further comprising controlling nonlinear optical processes induced by the laser pulse.

18. The method of claim 11, further comprising shaping the laser pulse in a binary manner.

19. The method of claim 11, further comprising receiving the monitored specimens from a building ventilation system.

20. The method of claim 11, further comprising receiving the monitored specimen from breath of a living human or animal.

21. The method of claim 11, further comprising receiving the monitored specimen at a security checkpoint.

22. The method of claim 11, further comprising using a programmable controller to positively identify a previously unknown agent, if the agent is automatically determined by the controller to be harmful.

23. A method of operating a system comprising:

(a) emitting at least one laser beam pulse into an area associated with a ventilation system;

(b) repetitively receiving air samples from the ventilation system;

(c) at least one programmable controller determining if an undesirable agent is present in the samples;

(d) the at least one controller enacting a countermeasure to reduce the harmfulness of the undesirable agent in response to step (b); and

(e) accessing programmable memory containing a library of acceptable background environmental specimens and undesirable environmental specimens, the controller comparing the detected characteristics to those stored in the memory.

24. The method of claim 23, further comprising the at least one controller automatically monitoring multiple discrete areas within the building.

25. The method of claim 23, further comprising the at least one controller automatically determining if the agent is moving between the discrete areas.

26. The method of claim 23, further comprising the at least one controller automatically changing the operation of the ventilation system to isolate contaminated ones of the discrete areas.

27. The method of claim 23, wherein the countermeasure further comprises automatically venting the agent to the atmosphere external to a building containing the ventilation system.

28. The method of claim 23, wherein the countermeasure further comprises automatically closing a door in a building containing the ventilation system.

29. The method of claim 23, wherein the countermeasure further comprises automatically flowing water into a building containing the ventilation system.

30. The method of claim 23, wherein the countermeasure further comprises automatically injecting at least one of:

a neutralizing agent and antidote, of the agent into a building containing the ventilation system.

31. The method of claim 23, further comprising varying a characteristic of the at least one laser beam pulse with a pulse shaper controlled by the at least one controller.

32. The method of claim 23, further comprising detecting a mass spectrum of the agent with a mass spectrometer connected to the at least one controller.

33. The method of claim 23, further comprising the at least one controller, positively identifying the previously unknown agent, if the agent is determined by the at least one controller to be harmful.

34. A method of operating a monitoring system comprising:

(a) emitting laser pulses at an environmental airborne specimen;

(b) sensing characteristics of the airborne specimen acted upon by at least one of the pulses;

(c) automatically determining if the airborne specimen is an acceptable agent or an undesirable agent; and

(d) using software instructions to access memory containing a library of characteristics of acceptable and undesirable environmental airborne specimens, and using software instructions to compare the real-time sensed characteristics to those stored in the memory.

35. The method of claim 34, further comprising conducting the sensing step in a building ventilation system.

36. The method of claim 34, further comprising receiving a signal from a sensor coupled to multiple zones of a building ventilation system, and a controller automatically and selectively determining if any of a variety of harmful agents are present in each building area separated by the zones in response to the received signal.

37. The method of claim 34, wherein the pulse shapes used to identify the agent were obtained using an evolutionary learning algorithm.

38. The method of claim 34, wherein the at least one laser beam pulse is transform limited and has a duration of less than about 50 femtoseconds.

39. The method of claim 34, further comprising a controller automatically varying a sampling rate of the sensing step depending upon the determining step.

40. The method of claim 34, further comprising using a programmable controller with software to characterize and correct for distortions in the pulses by varying shaping of the pulses, in a calculated rather than evolutionary learning manner.

41. A method of operating a building monitoring system comprising:

(a) emitting a laser beam pulse of less than about 50 femtoseconds;

(b) shaping the laser beam pulse;

(c) detecting characteristics of an environmental agent in the building ventilation system in response to steps (a) and (b);

(d) using a programmable controller to determine a characteristic of the agent, and positively identifying the agent, which was previously unknown to the controller if the agent is determined to be harmful.

42. The method of claim 41, further comprising the controller automatically monitoring multiple discrete areas within the building.

43. The method of claim 41, further comprising the controller automatically determining if the agent is moving between the discrete areas.

44. The method of claim 41, further comprising the controller automatically changing the operation of the ventilation system to isolate contaminated ones of the discrete areas.

45. The method of claim 41, wherein the countermeasure further comprises automatically venting the agent to the atmosphere external to a building containing the ventilation system.

46. The method of claim 41, wherein the countermeasure further comprises automatically closing a door in a building containing the ventilation system.

47. The method of claim 41, wherein the countermeasure further comprises automatically flowing water into a building containing the ventilation system.

48. The method of claim 41, wherein the countermeasure further comprises automatically injecting at least one of:

a neutralizing agent and antidote, of the agent into a building containing the ventilation system.

49. The method of claim 41, further comprising varying a characteristic of the pulse with a pulse shaper controlled by the controller.

50. The method of claim 41, further comprising detecting a mass spectrum of the agent with a mass spectrometer connected to the controller.

51. The method of claim 41, further comprising using the controller for characterization and compensation of undesired distortions in the pulse in a calculated manner.

52. The method of claim 41, wherein the agent is a chemical molecule.

53. The method of claim 41, wherein the agent is a biological pathogen.

54. The method of claim 41, wherein the agent is associated with a human breathable disease.

55. The method of claim 41, further comprising the controller automatically varying a sampling rate of the detector depending upon the determination results.

56. A method of monitoring comprising:

(a) monitoring a specimen in a repetitive manner;

(b) emitting shaped laser pulses at the specimen;

(c) electronically comparing characteristics obtained in response to the pulse interaction with the specimen, to a library database of acceptable background characteristics; and

(d) electronically determining if an undesirable disease is present in the specimen and if so, identifying the disease.

57. The method of claim 56, further comprising obtaining the specimen from a person'"'"'s breath.

58. The method of claim 56, further comprising obtaining the specimen from a building ventilation system.